Tanshinone I selectively suppresses pro-inflammatory genes expression in activated microglia and prevents nigrostriatal dopaminergic neurodegeneration in a mouse model of Parkinson's disease

Effect of Bacille-Calmette-Guerin vaccine against rotenone-induced Parkinson's disease: Role of neuroinflammation and neurotransmitters

BACKGROUND

Parkinson's disease (PD) is an extrapyramidal movement disorder associated with a hypokinetic condition generated by impairment in dopaminergic neuronal viability in the nigrostriatal region of the brain. Current medications can only provide symptomatic management; to date, no permanent cure is available. To compensate for this lacuna, researchers are gaining interest in antigen-based therapy, and Bacille-Calmette-Guerin (BCG) is one of the vaccines with a high safety margin that acts by stimulating immunoreactive T-cells in the CNS and reducing expression of pro-inflammatory cytokines including interleukin (IL)-1β and tumor necrotic factor (TNF-α) to produce neuroprotection. A previous study reported that BCG exerts a neuroprotective effect against several neurodegenerative disorders, such as Alzheimer's disease.

OBJECTIVE

The objective of this study is to explore the neuroprotective effect of the BCG vaccine against the rotenone model of PD.

METHODS

Rotenone (1.5 mg/kg, s.c) for 28 days, and BCG vaccine (2 × 107 cfu, i.p) single dose was injected to rats, and behavioral assessments were performed on the 21st and 28th day. On the 29th day, rats were sacrificed, and brains were isolated for biochemical and neurochemical estimation.

RESULTS

BCG vaccine significantly restored rotenone-induced motor deficits (open field test, narrow beam walk, and rotarod), biochemical levels (GSH, SOD, catalase, MDA, and nitrite), neurotransmitters (dopamine, 5-hydroxy tryptamine, norepinephrine, 3,4-dihydroxyphenylacetic acid, hemovanillic acid, and 5-hydroxy indoleacetic acid), and levels of inflammatory cytokines (IL-1β and TNF-α) in the striatum. It also prevents histopathological changes by reducing eosinophilic lesions in the striatum.

CONCLUSION

From the results, we conclude that BCG vaccine showed neuroprotection through antioxidant and anti-inflammatory effect. Thus, in the future, it can be used as a neuroprotective agent for other neurological disorders, including PD.

3-Hydroxytanshinone Inhibits the Activity of Hypoxia-Inducible Factor 1-α by Interfering with the Function of α-Enolase in the Glycolytic Pathway

Tumor cells in hypoxic conditions control cancer metabolism and angiogenesis by expressing HIF-1α. Tanshinone is a traditional Chinese medicine that has been shown to possess antitumor properties and exerts a therapeutic impact on angiogenesis. However, the precise molecular mechanism responsible for the antitumor activity of 3-Hydroxytanshinone (3-HT), a type of tanshinone, has not been fully understood. Therefore, our study aimed to investigate the mechanism by which 3-HT regulates the expression of HIF-1α. Our findings demonstrate that 3-HT inhibits HIF-1α activity and expression under hypoxic conditions. Additionally, 3-HT inhibits hypoxia-induced angiogenesis by suppressing the expression of VEGF. Moreover, 3-HT was found to directly bind to α-enolase, an enzyme associated with glycolysis, resulting in the suppression of its activity. This inhibition of α-enolase activity by 3-HT leads to the blockade of the glycolytic pathway and a decrease in glycolysis products, ultimately altering HIF1-α expression. Furthermore, 3-HT negatively regulates the expression of HIF-1α by altering the phosphorylation of AMP-activated protein kinase (AMPK). Our study's findings elucidate the mechanism by which 3-HT regulates HIF-1α through the inhibition of the glycolytic enzyme α-enolase and the phosphorylation of AMPK. These results suggest that 3-HT holds promise as a potential therapeutic agent for hypoxia-related angiogenesis and tumorigenesis.

Improvement effects of cyclic peptides from Annona squamosa on cognitive decline in neuroinflammatory mice

Cyclic peptides can resist enzymatic hydrolysis to pass through the intestine barrier, which may reduce the risk of mild cognition decline. But evidence is lacking on whether they work by alleviating neuroinflammation. A cylic peptide from Annona squamosa, Cylic(PIYAG), was biologically evaluated in vivo and in vitro. Cylic(PIYAG) enhanced the spatial memory ability of LPS-induced mice. And treatment with Cylic(PIYAG) markedly reduced the iNOS, MCP-1, TNF-α, and gp91phox expression induced by LPS. Cylic(PIYAG, 0.01, 0.05 and 0.2 μM) could significantly reduce the protein expression level of COX-2 and iNOS (P < 0.05) in BV2 cells. The concentration of Cylic(PIYAG) in blood reached a peak of 3.64 ± 1.22 μg/ml after intragastric administration in 1 h. And fluorescence microscope shows that Cylic(PIYAG) mainly locates and may play an anti-inflammatory role in the cytoplasm of microglia. This study demonstrates that the peptidic can prevent microglia activation, decrease the inflammatory reaction, improve the cognition of LPS-induced mice.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01441-8.

NF-κB/NLRP3 Translational Inhibition by Nanoligomer Therapy Mitigates Ethanol and Advanced Age-Related Neuroinflammation

Binge alcohol use is increasing among aged adults (>65 years). Alcohol-related toxicity in aged adults is associated with neurodegeneration, yet the molecular underpinnings of age-related sensitivity to alcohol are not well described. Studies utilizing rodent models of neurodegenerative disease reveal heightened activation of Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and Nod like receptor 3 (NLRP3) mediate microglia activation and associated neuronal injury. Our group, and others, have implicated hippocampal-resident microglia as key producers of inflammatory mediators, yet the link between inflammation and neurodegeneration has not been established in models of binge ethanol exposure and advanced age. Here, we report binge ethanol increased the proportion of NLRP3+ microglia in the hippocampus of aged (18-20 months) female C57BL/6N mice compared to young (3-4 months). In primary microglia, ethanol-induced expression of reactivity markers and NLRP3 inflammasome activation were more pronounced in microglia from aged mice compared to young. Making use of an NLRP3-specific inhibitor (OLT1177) and a novel brain-penetrant Nanoligomer that inhibits NF-κB and NLRP3 translation (SB_NI_112), we find ethanol-induced microglial reactivity can be attenuated by OLT1177 and SB_NI_112 in microglia from aged mice. In a model of intermittent binge ethanol exposure, SB_NI_112 prevented ethanol-mediated microglia reactivity, IL-1β production, and tau hyperphosphorylation in the hippocampus of aged mice. These data suggest early indicators of neurodegeneration occurring with advanced age and binge ethanol exposure are NF-κB- and NLRP3-dependent. Further investigation is warranted to explore the use of targeted immunosuppression via Nanoligomers to attenuate neuroinflammation after alcohol consumption in the aged.

Anti-Neuroinflammatory Effects of Adaptogens: A Mini-Review

Introduction: Adaptogens are a group of plants that exhibit complex, nonspecific effects on the human body, increasing its ability to adapt, develop resilience, and survive in stress conditions. They are found in many traditional medicinal systems and play a key role in restoring the body's strength and stamina. Research in recent years has attempted to elucidate the mechanisms behind their pharmacological effects, but it appears that these effects are difficult to define precisely and involve multiple molecular pathways. Neuroinflammation: In recent years, chronic inflammation has been recognized as one of the common features of many central nervous system disorders (dementia and other neurodegenerative diseases, depression, anxiety, ischemic stroke, and infections). Because of the specific nature of the brain, this process is called neuroinflammation, and its suppression can result in an improvement of patients' condition and may promote their recovery. Adaptogens as anti-inflammatory agents: As has been discovered, adaptogens display anti-inflammatory effects, which suggests that their application may be broader than previously thought. They regulate gene expression of anti- and proinflammatory cytokines (prostaglandins, leukotriens) and can modulate signaling pathways (e.g., NF-κB). Aim: This mini-review aims to present the anti-neuroinflammatory potential of the most important plants classified as adaptogens: Schisandra chinensis, Eleutherococcus senticosus, Rhodiola rosea and Withania somnifera.

What Can Inflammation Tell Us about Therapeutic Strategies for Parkinson's Disease?

Parkinson's disease (PD) is a common neurodegenerative disorder with a complicated etiology and pathogenesis. α-Synuclein aggregation, dopaminergic (DA) neuron loss, mitochondrial injury, oxidative stress, and inflammation are involved in the process of PD. Neuroinflammation has been recognized as a key element in the initiation and progression of PD. In this review, we summarize the inflammatory response and pathogenic mechanisms of PD. Additionally, we describe the potential anti-inflammatory therapies, including nod-like receptor pyrin domain containing protein 3 (NLRP3) inflammasome inhibition, nuclear factor κB (NF-κB) inhibition, microglia inhibition, astrocyte inhibition, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibition, the peroxisome proliferator-activated receptor γ (PPARγ) agonist, targeting the mitogen-activated protein kinase (MAPK) pathway, targeting the adenosine monophosphate-activated protein kinase (AMPK)-dependent pathway, targeting α-synuclein, targeting miRNA, acupuncture, and exercise. The review focuses on inflammation and will help in designing new prevention strategies for PD.

Co-assembled Supramolecular Hydrogel of Salvianolic Acid B and a Phosphopeptide for Enhanced Wound Healing

Supramolecular natural product gels (NPGs) have emerged as promising biomaterials for scalable and adjustable drug delivery systems. These gels possess biocompatibility, biodegradability, and the ability to mimic the extracellular matrix. Salvianolic acid B (SAB), derived from Salvia miltiorrhiza, a Chinese medicinal plant, exhibits various beneficial properties such as antioxidant, antifibrotic, and angiogenic effects. In our research, we serendipitously discovered that the co-assembly of SAB and a soluble phosphopeptide results in the formation of a robust and adhesive hydrogel termed 1&SAB hydrogel. This hydrogel effectively prolongs the retention time of the therapeutic agents on the skin's wound surface, thereby promoting wound healing. The hydrogel demonstrates antioxidant effects, enhances cell migration, accelerates angiogenesis, and inhibits scar hyperplasia. This innovative gel material offers a simple and efficient approach to managing skin wounds and holds promise for application in complex wound-healing treatments.

In Silico Discovery of Potential Inhibitors Targeting the RNA Binding Loop of ADAR2 and 5-HT2CR from Traditional Chinese Natural Compounds

Adenosine deaminase acting on RNA 2 (ADAR2) is an important enzyme involved in RNA editing processes, particularly in the conversion of adenosine to inosine in RNA molecules. Dysregulation of ADAR2 activity has been implicated in various diseases, including neurological disorders (including schizophrenia), inflammatory disorders, viral infections, and cancers. Therefore, targeting ADAR2 with small molecules presents a promising therapeutic strategy for modulating RNA editing and potentially treating associated pathologies. However, there are limited compounds that effectively inhibit ADAR2 reactions. This study therefore employed computational approaches to virtually screen natural compounds from the traditional Chinese medicine (TCM) library. The shortlisted compounds demonstrated a stronger binding affinity to the ADAR2 (<-9.5 kcal/mol) than the known inhibitor, 8-azanebularine (-6.8 kcal/mol). The topmost compounds were also observed to possess high binding affinity towards 5-HT2CR with binding energies ranging from -7.8 to -12.9 kcal/mol. Further subjecting the top ADAR2-ligand complexes to molecular dynamics simulations and molecular mechanics Poisson-Boltzmann surface area (MM/PBSA) calculations revealed that five potential hit compounds comprising ZINC000014637370, ZINC000085593577, ZINC000042890265, ZINC000039183320, and ZINC000101100339 had favorable binding free energies of -174.911, -137.369, -117.236, -67.023, and -64.913 kJ/mol, respectively, with the human ADAR2 protein. Residues Lys350, Cys377, Glu396, Cys451, Arg455, Ser486, Gln488, and Arg510 were also predicted to be crucial in ligand recognition and binding. This finding will provide valuable insights into the molecular interactions between ADAR2 and small molecules, aiding in the design of future ADAR2 inhibitors with potential therapeutic applications. The potential lead compounds were also profiled to have insignificant toxicities. A structural similarity search via DrugBank revealed that ZINC000039183320 and ZINC000014637370 were similar to naringin and naringenin, which are known adenosine deaminase (ADA) inhibitors. These potential novel ADAR2 inhibitors identified herein may be beneficial in treating several neurological disorders, cancers, viral infections, and inflammatory disorders caused by ADAR2 after experimental validation.

Dihydroisotanshinone I and BMAL-SIRT1 Pathway in an In Vitro 6-OHDA-Induced Model of Parkinson's Disease

Danshen has been widely used for the treatment of central nervous system diseases. We investigated the effect of dihydroisotanshinone I (DT), a compound extracted from Danshen, as well as the corresponding mechanisms in an in vitro-based 6-OHDA-induced Parkinson's disease (PD) model. SH-SY5Y human neuroblastoma cell lines were pretreated with 6-hydroxydopamine (6-OHDA) and challenged with DT. Subsequently, the cell viability and levels of reactive oxygen species (ROS) and caspase-3 were analyzed. The effect of DT on the 6-OHDA-treated SH-SY5Y cells and the expression of the core circadian clock genes were measured using a real-time quantitative polymerase chain reaction. Our results indicated that DT attenuated the 6-OHDA-induced cell death in the SH-SY5Y cells and suppressed ROS and caspase-3. Moreover, DT reversed both the RNA and protein levels of BMAL1 and SIRT1 in the 6-OHDA-treated SH-SY5Y cells. Additionally, the SIRT1 inhibitor attenuated the effect of DT on BMAL1 and reduced the cell viability. The DT and SIRT1 activators activated SIRT1 and BMAL1, and then reduced the death of the SH-SY5Y cells damaged by 6-OHDA. SIRT1 silencing was enhanced by DT and resulted in a BMAL1 downregulation and a reduction in cell viability. In conclusion, our investigation suggested that DT reduces cell apoptosis, including an antioxidative effect due to a reduction in ROS, and regulates the circadian genes by enhancing SIRT1 and suppressing BMAL1. DT may possess novel therapeutic potential for PD in the future, but further in vivo studies are still needed.

Tanshinone I specifically suppresses NLRP3 inflammasome activation by disrupting the association of NLRP3 and ASC

BACKGROUND

Abnormal activation of NLRP3 inflammasome is related to a series of inflammatory diseases, including type 2 diabetes, gouty arthritis, non-alcoholic steatohepatitis (NASH), and neurodegenerative disorders. Therefore, targeting NLRP3 inflammasome is regarded as a potential therapeutic strategy for many inflammatory diseases. A growing number of studies have identified tanshinone I (Tan I) as a potential anti-inflammatory agent because of its good anti-inflammatory activity. However, its specific anti-inflammatory mechanism and direct target are unclear and need further study.

METHODS

IL-1β and caspase-1 were detected by immunoblotting and ELISA, and mtROS levels were measured by flow cytometry. Immunoprecipitation was used to explore the interaction between NLRP3, NEK7 and ASC. In a mouse model of LPS-induced septic shock, IL-1β levels in peritoneal lavage fluid and serum were measured by ELISA. Liver inflammation and fibrosis in the NASH model were analyzed by HE staining and immunohistochemistry.

RESULTS

Tan I inhibited the activation of NLRP3 inflammasome in macrophages, but had no effect on the activation of AIM2 or NLRC4 inflammasome. Mechanistically, Tan I inhibited NLRP3 inflammasome assembly and activation by targeting NLRP3-ASC interaction. Furthermore, Tan I exhibited protective effects in mouse models of NLRP3 inflammasome-mediated diseases, including septic shock and NASH.

CONCLUSIONS

Tan I specifically suppresses NLRP3 inflammasome activation by disrupting the association of NLRP3 and ASC, and exhibits protective effects in mouse models of LPS-induced septic shock and NASH. These findings suggest that Tan I is a specific NLRP3 inhibitor and may be a promising candidate for treating NLRP3 inflammasome-related diseases.

The Flavonoid Agathisflavone Directs Brain Microglia/Macrophages to a Neuroprotective Anti-Inflammatory and Antioxidant State via Regulation of NLRP3 Inflammasome

Agathisflavone, purified from Cenostigma pyramidale (Tul.) has been shown to be neuroprotective in in vitro models of glutamate-induced excitotoxicity and inflammatory damage. However, the potential role of microglial regulation by agathisflavone in these neuroprotective effects is unclear. Here we investigated the effects of agathisflavone in microglia submitted to inflammatory stimulus in view of elucidating mechanisms of neuroprotection. Microglia isolated from cortices of newborn Wistar rats were exposed to Escherichia coli lipopolysaccharide (LPS, 1 µg/mL) and treated or not with agathisflavone (1 µM). Neuronal PC12 cells were exposed to a conditioned medium from microglia (MCM) treated or not with agathisflavone. We observed that LPS induced microglia to assume an activated inflammatory state (increased CD68, more rounded/amoeboid phenotype). However, most microglia exposed to LPS and agathisflavone, presented an anti-inflammatory profile (increased CD206 and branched-phenotype), associated with the reduction in NO, GSH mRNA for NRLP3 inflammasome, IL1-β, IL-6, IL-18, TNF, CCL5, and CCL2. Molecular docking also showed that agathisflavone bound at the NLRP3 NACTH inhibitory domain. Moreover, in PC12 cell cultures exposed to the MCM previously treated with the flavonoid most cells preserved neurites and increased expression of β-tubulin III. Thus, these data reinforce the anti-inflammatory activity and the neuroprotective effect of agathisflavone, effects associated with the control of NLRP3 inflammasome, standing out it as a promising molecule for the treatment or prevention of neurodegenerative diseases.

Intracellular DAMPs in Neurodegeneration and Their Role in Clinical Therapeutics

Neuroinflammation is the major implication of neurodegeneration. This is a complex process which initiates from the cellular injury triggering the innate immune system which gives rise to damage-associated molecular patterns (DAMPs) which are also recognized as endogenous danger indicators. These originate from various compartments of the cell under pathological stimulus. These are very popular candidates having their origin in the intracellular compartments and organelles of the cell and may have their site of action itself in the intracellular or at the extracellular spaces. Under the influence of the pathological stimuli, they interact with the pattern-recognition receptor to initiate their pro-inflammatory cascade followed by the cytokine release. This provides a good opportunity for diagnostic and therapeutic interventions creating better conditions for repair and reversal. Since the major contributors arise from the intracellular compartment, in this review, we have attempted to focus on the DAMP molecules arising from the intracellular compartments and their specific roles in the neurodegenerative events explaining their downstream mediators and signaling. Moreover, we have tried to cover the latest interventions in terms of DAMPs as clinical biomarkers which can assist in detecting the disease and also target it to reduce the innate-immune activation response which can help in reducing the sterile neuroinflammation having an integral role in the neurodegenerative processes.

Tanshinone I: Pharmacological activities, molecular mechanisms against diseases and future perspectives

BACKGROUND

Tanshinone I (Tan I) is known as one of the important active components in Salvia miltiorrhiza. In recent years, Tan I has received a substantial amount of attention from the research community for various studies being updated and has been shown to possess favorable activities including anti-oxidative stress, regulation of cell autophagy or apoptosis, inhibition of inflammation, etc. PURPOSE: To summarize the investigation progress on the anti-disease efficacy and effect mechanism of Tan I in recent years, and provide perspectives for future study on the active ingredient.

METHOD

Web of Science and PubMed databases were used to search for articles related to "Tanshinone I" published from 2010 to 2022. Proteins or genes and signaling pathways referring to Tan I against diseases were summarized and classified along with its different therapeutic actions. Protein-protein interaction (PPI) analysis was then performed, followed by molecular docking between proteins with high node degree and Tan I, as well as bioinformactic analysis including GO, KEGG and DO enrichment analysis with the collected proteins or genes.

RESULTS

Tan I shows multiple therapeutic effects, including protection of the cardiovascular system, anti-cancer, anti-inflammatory, anti-neurodegenerative diseases, etc. The targets (proteins or genes) affected by Tan I against diseases involve Bcl-2, Bid, ITGA2, PPAT, AURKA, VEGF, PI3K, AKT, PRK, JNK, MMP9, ABCG2, CASP3, Cleaved-caspase-3, AMPKα, PARP, etc., and the regulatory pathways refer to Akt/Nrf2, SAPK/JNK, PI3K/Akt/mTOR, JAK/STAT3, ATF-2/ERK, etc. What's more, AKT1, CASP3, and STAT3 were predicted as the key action targets for Tan I by PPI analysis combined with molecular docking, and the potential therapeutic effects mechanisms against diseases were also further predicted by bioinformatics analyses based on the reported targets, providing new insights into the future investigation and helping to facilitate the drug development of Tan I.

New opportunities and challenges of natural products research: When target identification meets single-cell multiomics

Natural products, and especially the active ingredients found in traditional Chinese medicine (TCM), have a thousand-year-long history of clinical use and a strong theoretical basis in TCM. As such, traditional remedies provide shortcuts for the development of original new drugs in China, and increasing numbers of natural products are showing great therapeutic potential in various diseases. This paper reviews the molecular mechanisms of action of natural products from different sources used in the treatment of inflammatory diseases and cancer, introduces the methods and newly emerging technologies used to identify and validate the targets of natural active ingredients, enumerates the expansive list of TCM used to treat inflammatory diseases and cancer, and summarizes the patterns of action of emerging technologies such as single-cell multiomics, network pharmacology, and artificial intelligence in the pharmacological studies of natural products to provide insights for the development of innovative natural product-based drugs. Our hope is that we can make use of advances in target identification and single-cell multiomics to obtain a deeper understanding of actions of mechanisms of natural products that will allow innovation and revitalization of TCM and its swift industrialization and internationalization.

Salvianolic acid B inhibits RAW264.7 cell polarization towards the M1 phenotype by inhibiting NF-κB and Akt/mTOR pathway activation

M1 macrophages secrete a large number of proinflammatory factors and promote the expansion of atherosclerotic plaques and processes. Salvianolic acid B (Sal B) exerts anti-inflammatory, antitumor and other effects, but no study has addressed whether Sal B can regulate the polarization of macrophages to exert these anti-atherosclerotic effects. Therefore, we investigated the inhibition of Sal B in M1 macrophage polarization and the underlying mechanism. The effects of different treatments on cell viability, gene expression and secretion of related proteins, phenotypic markers and cytokines were detected by MTT and western blot assays, RT‒qPCR and ELISAs. Cell viability was not significantly changed when the concentration of Sal B was less than 200 μM, and Lipopolysaccharide (LPS) (100 ng/mL) + interferon-γ (IFN-γ) (2.5 ng/mL) successfully induced M1 polarization. RT‒qPCR and ELISAs indicated that Sal B can downregulate M1 marker (Inducible Nitric Oxide Synthase (iNOS), Tumor Necrosis Factor-α (TNF-α), and Interleukin-6 (IL-6)) and upregulate M2 marker (Arginase-1 (Arg-1) and Interleukin-10 (IL-10)) expression. Western blotting was performed to measure the expression of Nuclear Factor-κB (NF-κB), p-Akt, p-mTOR, LC3-II, Beclin-1, and p62, and the results suggested that Sal B inhibits the M1 polarization of RAW264.7 macrophages by promoting autophagy via the NF-κB signalling pathway. The study indicated that Sal B inhibits M1 macrophage polarization by inhibiting NF-κB signalling pathway activation and downregulating Akt/mTOR activation to promote autophagy.

Research and Development of Natural Product Tanshinone I: Pharmacology, Total Synthesis, and Structure Modifications

Salvia miltiorrhiza (S. miltiorrhiza), which has been used for thousands of years to treat cardiovascular diseases, is a well-known Chinese medicinal plant. The fat-soluble tanshinones in S. miltiorrhiza are important biologically active ingredients including tanshinone I, tanshinone IIA, dihydrotanshinone, and cryptotanshinone. Tanshinone I, a natural diterpenoid quinone compound widely used in traditional Chinese medicine, has a wide range of biological effects including anti-cancer, antioxidant, neuroprotective, and anti-inflammatory activities. To further improve its potency, water solubility, and bioavailability, tanshinone I can be used as a platform for drug discovery to generate high-quality drug candidates with unique targets and enhanced drug properties. Numerous derivatives of tanshinone I have been developed and have contributed to major advances in the identification of new drugs to treat human cancers and other diseases and in the study of related molecular mechanisms. This review focuses on the structural modification, total synthesis, and pharmacology of tanshinone I. We hope that this review will help understanding the research progress in this field and provide constructive suggestions for further research on tanshinone I.

The Expression Profiles of the Salvia miltiorrhiza 3-Hydroxy-3-methylglutaryl-coenzyme A Reductase 4 Gene and Its Influence on the Biosynthesis of Tanshinones

Salvia miltiorrhiza is a medicinal plant that synthesises biologically-active tanshinones with numerous therapeutic properties. An important rate-limiting enzyme in the biosynthesis of their precursors is 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR). This study presents the organ-specific expression profile of the S. miltiorrhiza HMGR4 gene and its sensitivity to potential regulators, viz. gibberellic acid (GA₃), indole-3-acetic acid (IAA) and salicylic acid (SA). In addition, it demonstrates the importance of the HMGR4 gene, the hormone used, the plant organ, and the culture environment for the biosynthesis of tanshinones. HMGR4 overexpression was found to significantly boost the accumulation of dihydrotanshinone I (DHTI), cryptotanshinone (CT), tanshinone I (TI) and tanshinone IIA (TIIA) in roots by 0.44 to 5.39 mg/g dry weight (DW), as well as TIIA in stems and leaves. S. miltiorrhiza roots cultivated in soil demonstrated higher concentrations of the examined metabolites than those grown in vitro. GA₃ caused a considerable increase in the quantity of CT (by 794.2 µg/g DW) and TIIA (by 88.1 µg/g DW) in roots. In turn, IAA significantly inhibited the biosynthesis of the studied tanshinones in root material.

Natural Products as Novel Neuroprotective Agents; Computational Predictions of the Molecular Targets, ADME Properties, and Safety Profile

Neurodegenerative diseases (NDs) are one of the most challenging public health issues. Despite tremendous advances in our understanding of NDs, little progress has been made in establishing effective treatments. Natural products may have enormous potential in preventing and treating NDs by targeting microglia; yet, there have been several clinical concerns about their usage, primarily due to a lack of scientific evidence for their efficacy, molecular targets, physicochemical properties, and safety. To solve this problem, the secondary bioactive metabolites derived from neuroprotective medicinal plants were identified and selected for computational predictions for anti-inflammatory activity, possible molecular targets, physicochemical properties, and safety evaluation using PASS online, Molinspiration, SwissADME, and ProTox-II, respectively. Most of the phytochemicals were active as anti-inflammatory agents as predicted using the PASS online webserver. Moreover, the molecular target predictions for some phytochemicals were similar to the reported experimental targets. Moreover, the phytochemicals that did not violate important physicochemical properties, including blood-brain barrier penetration, GI absorption, molecular weight, and lipophilicity, were selected for further safety evaluation. After screening 54 neuroprotective phytochemicals, our findings suggest that Aromatic-turmerone, Apocynin, and Matrine are the most promising compounds that could be considered when designing novel neuroprotective agents to treat neurodegenerative diseases via modulating microglial polarization.

Tanshinone I Mitigates Steroid-Induced Osteonecrosis of the Femoral Head and Activates the Nrf2 Signaling Pathway in Rats

Steroid-induced osteonecrosis of the femoral head (SIONFH) is a frequent orthopedic disease caused by long-term or high-dose administration of corticosteroids. Tanshinone I (TsI), a flavonoid compound isolated from Salvia miltiorrhiza Bunge, has been reported to inhibit osteoclastic differentiation in vitro. This study aimed to investigate whether TsI can ameliorate SIONFH. Herein, SIONFH was induced by intraperitoneal injection of 20 μg/kg lipopolysaccharide every 24 h for 2 days, followed by an intramuscular injection of 40 mg/kg methylprednisolone every 24 h for 3 days. Four weeks after the final injection of methylprednisolone, the rats were intraperitoneally administrated with low-dose (5 mg/kg) and high-dose (10 mg/kg) TsI once daily for 4 weeks. Results showed that TsI significantly alleviated osteonecrotic lesions of the femoral heads as determined by micro-CT analysis. Furthermore, TsI increased alkaline phosphatase activity and expressions of osteoblastic markers including osteocalcin, type I collagen, osteopontin, and Runt-related transcription factor 2 and decreased tartrate-resistant acid phosphatase activity and expressions of osteoclastic markers including cathepsin K and acid phosphatase 5. TsI also reduced inflammatory response and oxidative stress and activated the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway in the femoral heads. Taken together, our findings show that TsI can relieve SIONFH, indicating that it may be a candidate for preventing SIONFH.

An image-based fingerprint-efficacy screening strategy for uncovering active compounds with interactive effects in Yindan Xinnaotong soft capsule

BACKGROUND

Yindan Xinnaotong soft capsule (YDXNT) is a clinically effective herbal prescription used for the treatment of cardiovascular and cerebrovascular diseases. Since Chinese medicines (CMs) exert their effects via a "multiple-components and multiple-targets" mode, discovery of the active compounds with interactive effects may contribute to reveal their mechanisms of action.

PURPOSE

This study aimed to establish an image-based fingerprint-efficacy screening strategy to identify active compounds with interaction effects from CM prescription, using YDXNT to inhibit microglia-mediated neuroinflammation as an instance.

METHODS

A multi-component random content-oriented chemical library of YDXNT was constructed by uniform design, and their chemical fingerprint was profiled by liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS) methods. Then the neuroinflammation activities of chemical library members of YDXNT were determined by image-based dual phenotypic quantification. Subsequently, fingerprint-efficacy correlation and random forest analysis were applied to predict the potentially active compounds with interactive effects. Finally, the interactive effects among the active compounds were confirmed by quantitative polymerase chain reaction (qPCR) and apoptosis analysis, and network pharmacology was applied to explore the possible mechanisms.

RESULTS

Image-based fingerprint-efficacy correlation analysis revealed that six tanshinones (TNs) and four flavonoids (FAs) were potential anti-neuroinflammatory compounds. The inter-family of TNs and FAs possessed obvious interactive effects (combination index ≤ 0.825). Moreover, the combination of scutellarein and tanshinone I (2:1, w/w) was discovered as the possible interactive combinatorial components, which, comparing with individual scutellarein or tanshinone I, shown more powerful effects on anti-inflammatory and anti-apoptotic effects in lipopolysaccharide (LPS)-induced BV2 cells. Network pharmacology showed that the active compounds might suppress microglia-mediated neuroinflammation via multiple targets in the T cell receptor, Jak-STAT, and Toll-like receptor signaling pathways.

CONCLUSION

The image-based fingerprint-efficacy strategy simplifies the screening process of efficacious component combinations in CMs for complex diseases, which also offers a promising approach to explore the integrative therapeutic mechanisms of CMs.

Phytochemicals as inhibitors of tumor necrosis factor alpha and neuroinflammatory responses in neurodegenerative diseases

Inflammatory processes and proinflammatory cytokines have a key role in the cellular processes of neurodegenerative diseases and are linked to the pathogenesis of functional and mental health disorders. Tumor necrosis factor alpha has been reported to play a major role in the central nervous system in Alzheimer’s disease, Parkinson’s disease and amyotrophic lateral sclerosis and many other neurodegenerative diseases. Therefore, a potent proinflammatory/proapoptotic tumor necrosis factor alpha could be a strong candidate for targeted therapy. Plant derivatives have now become promising candidates as therapeutic agents because of their antioxidant and chemical characteristics, and anti-inflammatory features. Recently, phytochemicals including flavonoids, terpenoids, alkaloids, and lignans have generated interest as tumor necrosis factor alpha inhibitor candidates for a number of diseases involving inflammation within the nervous system. In this review, we discuss how phytochemicals as tumor necrosis factor alpha inhibitors are a therapeutic strategy targeting neurodegeneration.

Dysregulated phosphoinositide 3-kinase signaling in microglia: shaping chronic neuroinflammation

Microglia are integral mediators of innate immunity within the mammalian central nervous system. Typical microglial responses are transient, intending to restore homeostasis by orchestrating the removal of pathogens and debris and the regeneration of damaged neurons. However, prolonged and persistent microglial activation can drive chronic neuroinflammation and is associated with neurodegenerative disease. Recent evidence has revealed that abnormalities in microglial signaling pathways involving phosphatidylinositol 3-kinase (PI3K) and protein kinase B (AKT) may contribute to altered microglial activity and exacerbated neuroimmune responses. In this scoping review, the known and suspected roles of PI3K-AKT signaling in microglia, both during health and pathological states, will be examined, and the key microglial receptors that induce PI3K-AKT signaling in microglia will be described. Since aberrant signaling is correlated with neurodegenerative disease onset, the relationship between maladapted PI3K-AKT signaling and the development of neurodegenerative disease will also be explored. Finally, studies in which microglial PI3K-AKT signaling has been modulated will be highlighted, as this may prove to be a promising therapeutic approach for the future treatment of a range of neuroinflammatory conditions.

Mechanisms Involved in Microglial-Interceded Alzheimer's Disease and Nanocarrier-Based Treatment Approaches

Alzheimer's disease (AD) is a common neurodegenerative disorder accountable for dementia and cognitive dysfunction. The etiology of AD is complex and multifactorial in origin. The formation and deposition of amyloid-beta (Aβ), hyperphosphorylated tau protein, neuroinflammation, persistent oxidative stress, and alteration in signaling pathways have been extensively explored among the various etiological hallmarks. However, more recently, the immunogenic regulation of AD has been identified, and macroglial activation is considered a limiting factor in its etiological cascade. Macroglial activation causes neuroinflammation via modulation of the NLRP3/NF-kB/p38 MAPKs pathway and is also involved in tau pathology via modulation of the GSK-3β/p38 MAPK pathways. Additionally, microglial activation contributes to the discrete release of neurotransmitters and an altered neuronal synaptic plasticity. Therefore, activated microglial cells appear to be an emerging target for managing and treating AD. This review article discussed the pathology of microglial activation in AD and the role of various nanocarrier-based anti-Alzeihmenr's therapeutic approaches that can either reverse or inhibit this activation. Thus, as a targeted drug delivery system, nanocarrier approaches could emerge as a novel means to overcome existing AD therapy limitations.

Developmental toxicity of cryptotanshinone on the early-life stage of zebrafish development

Cryptotanshinone (Cry) has multiple potential functions in treating different diseases. Most studies on Cry focus on its pharmacological effects and mechanisms, but toxicological reports on Cry are rare. Zebrafish is used as a model organism in drug development as it saves costs and time. This work aimed to investigate the toxicity of Cry on zebrafish. Results showed that growth retardation, pericardial edema, and scoliosis occurred when zebrafish embryos were exposed to Cry, indicating its teratogenic effects. Cell apoptosis was observed in the brainstem area of embryos using acridine orange staining, and qPCR showed that caspase-3 was increased in Cry-exposed embryos. The results of locomotor activity and touched-evoke escape reaction experiments showed that Cry significantly reduced the swimming speed and escape reaction time of larvae.

Suppression of Mitochondria-Related Bioenergetics Collapse and Redox Impairment by Tanshinone I, a Diterpenoid Found in Salvia miltiorrhiza Bunge (Danshen), in the Human Dopaminergic SH-SY5Y Cell Line Exposed to Chlorpyrifos

Tanshinone I (T-I, C₁₈H₁₂O₃) is a diterpene found in Salvia miltiorrhiza Bunge (Danshen) and promotes cytoprotection in several experimental models. Chlorpyrifos (CPF) is an agrochemical that causes bioenergetics failure, redox impairment, inflammation, and cell death in animal tissues. Here, we investigated whether T-I would be able to prevent the consequences resulting from the exposure of the human dopaminergic SH-SY5Y cells to CPF. We found that a pretreatment with T-I at 2.5 µM for 2 h suppressed lipid peroxidation and protein carbonylation and nitration on the membranes of mitochondria extracted from the CPF-treated cells. Also, T-I reduced the production of radical superoxide (O₂^-•) by the mitochondria of the CPF-challenged cells. The production of nitric oxide (NO^•) and hydrogen peroxide (H₂O₂) was also decreased by T-I in the cells exposed to CPF. The CPF-induced decrease in the activity of the complexes I-III, II-III, and V was abolished by a pretreatment with T-I. Loss of mitochondrial membrane potential (ΔΨ_m) and reduction in the production of adenosine triphosphate (ATP) were also prevented by T-I in the CPF-treated cells. T-I also induced anti-inflammatory effects in the CPF-treated cells by decreasing the levels of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) and the activity of the nuclear factor-κB (NF-κB). Inhibition of heme oxygenase-1 (HO-1) or silencing of the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) blocked the T-I-promoted mitochondrial protection and anti-inflammatory action. Overall, T-I depended on the Nrf2/HO-1 axis to prevent the deleterious effects caused by CPF in this experimental model.

Tanshinones and their Derivatives: Heterocyclic Ring-Fused Diterpenes of Biological Interest

The available scientific literature regarding tanshinones is very abundant, and after its review, it is noticeable that most of the articles focus on the properties of tanshinone I, cryptotanshinone, tanshinone IIA, sodium tanshinone IIA sulfonate and the dried root extract of Salvia miltiorrhiza (Tan- Shen). However, although these products have demonstrated important biological properties in both in vitro and in vivo models, their poor solubility and bioavailability have limited their clinical applications. For these reasons, many studies have focused on the search for new pharmaceutical formulations for tanshinones, as well as the synthesis of new derivatives that improve their biological properties. To provide new insights into the critical path ahead, we systemically reviewed the most recent advances (reported since 2015) on tanshinones in scientific databases (PubMed, Web of Science, Medline, Scopus, and Clinical Trials). With a broader perspective, we offer an update on the last five years of new research on these quinones, focusing on their synthesis, biological activity on noncommunicable diseases and drug delivery systems, to support future research on its clinical applications.

Monoamine Oxidase Inhibition by Major Tanshinones from Salvia miltiorrhiza and Selective Muscarinic Acetylcholine M4 Receptor Antagonism by Tanshinone I

Monoamine oxidases (MAOs) and muscarinic acetylcholine receptors (mAChRs) are considered important therapeutic targets for Parkinson's disease (PD). Lipophilic tanshinones are major phytoconstituents in the dried roots of Salvia miltiorrhiza that have demonstrated neuroprotective effects against dopaminergic neurotoxins and the inhibition of MAO-A. Since MAO-B inhibition is considered an effective therapeutic strategy for PD, we tested the inhibitory activities of three abundant tanshinone congeners against recombinant human MAO (hMAO) isoenzymes through in vitro experiments. In our study, tanshinone I (1) exhibited the highest potency against hMAO-A, followed by tanshinone IIA and cryptotanshinone, with an IC50 less than 10 µM. They also suppressed hMAO-B activity, with an IC50 below 25 µM. Although tanshinones are known to inhibit hMAO-A, their enzyme inhibition mechanism and binding sites have yet to be investigated. Enzyme kinetics and molecular docking studies have revealed the mode of inhibition and interactions of tanshinones during enzyme inhibition. Proteochemometric modeling predicted mAChRs as possible pharmacological targets of 1, and in vitro functional assays confirmed the selective M4 antagonist nature of 1 (56.1% ± 2.40% inhibition of control agonist response at 100 µM). These findings indicate that 1 is a potential therapeutic molecule for managing the motor dysfunction and depression associated with PD.

Tanshinone I exerts cardiovascular protective effects in vivo and in vitro through inhibiting necroptosis via Akt/Nrf2 signaling pathway

BACKGROUND

Tanshinone I (TI) is a primary component of Salvia miltiorrhiza Bunge (Danshen), which confers a favorable role in a variety of pharmacological activities including cardiovascular protection. However, the exact mechanism of the cardiovascular protection activity of TI remains to be illustrated. In this study, the cardiovascular protective effect and its mechanism of TI were investigated.

METHODS

In this study, tert-butyl hydroperoxide (t-BHP)-stimulated H9c2 cells model was employed to investigate the protective effect in vitro. The cell viability was determined by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay and lactate dehydrogenase (LDH) kit. The reactive-oxygen-species (ROS) level and mitochondrial membrane potential (MMP) were investigated by the flow cytometry and JC-1 assay, respectively. While in vivo experiment, the cardiovascular protective effect of TI was determined by using myocardial ischemia-reperfusion (MI/R) model including hematoxylin-eosin (H&E) staining assay and determination of superoxide dismutase (SOD) and malondialdehyde (MDA). Tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) release were detected by Enzyme-linked immunosorbent assay (ELISA). Receptor interacting protein kinase 1 (RIP1), receptor interacting protein kinase 3 (RIP3), receptor interacting protein kinase 3 (MLKL), protein kinase B (Akt), Nuclear factor erythroid 2 related factor 2 (Nrf2), Heme oxygenase-1 (HO-1) and NAD(P)H: quinone oxidoreductase-1 (NQO-1) were determined by western blotting.

RESULTS

Our data demonstrated that TI pretreatment attenuated t-BHP and MI/R injury-induced necroptosis by inhibiting the expression of p-RIP1, p-RIP3, and p-MLKL. TI activated the Akt/Nrf2 pathway to promote the expression of antioxidant-related proteins such as phosphorylation of Akt, nuclear factor erythroid 2 related factor 2 (Nrf2), quinone oxidoreductase-1 (NQO-1) and heme oxygenase-1 (HO-1) expression in t-BHP-stimulated H9c2 cells. TI relieved oxidative stress by mitigating ROS generation and reversing MMP loss. In vivo experiment, TI made electrocardiograph (ECG) recovery better and lessened the degree of myocardial tissue damage. The counts of white blood cell (WBC), neutrophil (Neu), lymphocyte (Lym), and the release of TNF-α and IL-6 were reversed by TI treatment. SOD level was increased, while MDA level was decreased by TI treatment.

CONCLUSION

Collectively, our findings indicated that TI exerted cardiovascular protective activities in vitro and in vivo through suppressing RIP1/RIP3/MLKL and activating Akt/Nrf2 signaling pathways, which could be developed into a cardiovascular protective agent.

Flavonoids, the Family of Plant-derived Antioxidants making inroads into Novel Therapeutic Design against IR-induced Oxidative Stress in Parkinson's Disease

Background:

Ionizing radiation from telluric sources is unceasingly an unprotected pitfall to humans. Thus, the foremost contributors to human exposure are global and medical radiations. Various evidences assembled during preceding years reveal the pertinent role of ionizing radiation-induced oxidative stress in the progression of neurodegenerative insults, such as Parkinson’s disease, which have been contributing to increased proliferation and generation of reactive oxygen species.

Objective:

This review delineates the role of ionizing radiation-induced oxidative stress in Parkinson’s disease and proposes novel therapeutic interventions of flavonoid family, offering effective management and slowing down the progression of Parkinson’s disease.

Methods:

Published papers were searched in MEDLINE, PubMed, etc., published to date for in-depth database collection.

Results:

The oxidative damage may harm the non-targeted cells. It can also modulate the functions of the central nervous system, such as protein misfolding, mitochondria dysfunction, increased levels of oxidized lipids, and dopaminergic cell death, which accelerate the progression of Parkinson’s disease at the molecular, cellular, or tissue levels. In Parkinson’s disease, reactive oxygen species exacerbate the production of nitric oxides and superoxides by activated microglia, rendering death of dopaminergic neuronal cell through different mechanisms.

Conclusion:

Rising interest has extensively engrossed in the clinical trial designs based on the plant-derived family of antioxidants. They are known to exert multifarious impact on neuroprotection via directly suppressing ionizing radiation-induced oxidative stress and reactive oxygen species production or indirectly increasing the dopamine levels and activating the glial cells.

A network-based method for mechanistic investigation and neuroprotective effect on treatment of tanshinone Ⅰ against ischemic stroke in mouse

ETHNOPHARMACOLOGICAL RELEVANCE

Tanshinone-Ⅰ (TSNⅠ), a member of the mainly active components of Salvia miltiorrhiza Bunge (Dan Shen), which is widely used for the treatment for modern clinical diseases including cardiovascular and cerebrovascular diseases, has been reported to show the properties of anti-oxidation, anti-inflammation, neuroprotection and other pharmacological actions. However, whether TSNⅠ can improve neuron survival and neurological function against transient focal cerebral ischemia (tMCAO) in mice is still a blank field.

AIM OF THE STUDY

This study aims to investigate the neuroprotective effects of TSNⅠ on ischemic stroke (IS) induced by tMCAO in mice and explore the potential mechanism of TSNⅠ against IS by combining network pharmacology approach and experimental verification.

MATERIALS AND METHODS

In this study, the pivotal candidate targets of TSNⅠ against IS were screened by network pharmacology firstly. Enrichment analysis and molecular docking of those targets were performed to identify the possible mechanism of TSNⅠ against IS. Afterwards, experiments were carried out to further verify the mechanism of TSNⅠ against IS. The infarct volume and neurological deficit were evaluated by 2, 3, 5-triphenyl tetrazolium chloride (TTC) staining and Longa respectively. Immunohistochemistry was used to observe neuronal death in the hippocampus and cortical regions by detecting the change of NeuN. The predicting pathways of signaling-related proteins were assessed by Western blot in vitro and in vivo experiments.

RESULTS

In vivo, TSNⅠ was found to dose-dependently decrease mice's cerebral infarct volume induced by tMCAO. In vitro, pretreatment with TSNⅠ could increase cell viability of HT-22 cell following oxygen-glucose deprivation (OGD/R). Moreover, the results showed that 125 candidate targets were identified, Protein kinase B (AKT) signaling pathway was significantly enriched by Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis and mitogen-activated protein kinases 1 (MAPK1) and AKT1 could be bound to TSNⅠ more firmly by molecular docking analysis, which implies that TSNⅠ may play a role in neuroprotection through activating AKT and MAPK signaling pathways. Meanwhile, TSNⅠ was confirmed to significantly protect neurons from injury induced by IS through activating AKT and MAPK signaling pathways.

CONCLUSION

In conclusion, our study clarifies that the mechanism of TSNⅠ against IS might be related to AKT and MAPK signaling pathways, which may provide the basic evidence for further development and utilization of TSNⅠ.

Tanshinone IIA: A phytochemical as a promising drug candidate for neurodegenerative diseases

Tanshinones, lipophilic diterpenes isolated from the rhizome of Salvia miltiorrhiza, have diverse pharmacological activities against human ailments including neurological diseases. In fact, tanshinones have been used to treat heart diseases, stroke, and vascular diseases in traditional Chinese medicine. During the last decade, tanshinones have been the most widely studied phytochemicals for their neuroprotective effects against experimental models of cerebral ischemia and Alzheimer's diseases. Importantly, tanshinone IIA, mostly studied tanshinone for biological activities, is recently reported to attenuate blood-brain barrier permeability among stroke patients, suggesting tanshinone IIA as an appealing therapeutic candidate for neurological diseases. Tanshinone I and IIA are also effective in experimental models of Parkinson's disease, Multiple sclerosis, and other neuroinflammatory diseases. In addition, several experimental studies suggested the pleiotropic neuroprotective effects of tanshinones such as anti-inflammatory, antioxidant, anti-apoptotic, and BBB protectant further value aiding to tanshinone as an appealing therapeutic strategy in neurological diseases. Therefore, in this review, we aimed to compile the recent updates and cellular and molecular mechanisms of neuroprotection of tanshinone IIA in diverse neurological diseases.

Nor-abietane Diterpenoids from Perovskia abrotanoides Roots with Anti-inflammatory Potential

Fractionation of an EtOAc extract of the roots of Perovskia abrotanoides yielded 28 diterpenoids, including 12 new analogues, 1-12. The structures of these diterpenoids were established using comprehensive spectroscopic data analysis, including 1D and 2D NMR, high-resolution electrospray ionization mass spectrometry, electronic circular dichroism spectroscopy, and comparison with literature data. The extract and some of the tested compounds showed significant anti-inflammatory activity on J774A.1 macrophage cells stimulated with E. coli lipopolysaccharide. In particular, the tested compounds significantly inhibited the release of nitric oxide and the expression of related proinflammatory enzymes, such as inducible nitric oxide synthase.

Microglia Specific Drug Targeting Using Natural Products for the Regulation of Redox Imbalance in Neurodegeneration

Microglia, a type of innate immune cell of the brain, regulates neurogenesis, immunological surveillance, redox imbalance, cognitive and behavioral changes under normal and pathological conditions like Alzheimer's, Parkinson's, Multiple sclerosis and traumatic brain injury. Microglia produces a wide variety of cytokines to maintain homeostasis. It also participates in synaptic pruning and regulation of neurons overproduction by phagocytosis of neural precursor cells. The phenotypes of microglia are regulated by the local microenvironment of neurons and astrocytes via interaction with both soluble and membrane-bound mediators. In case of neuron degeneration as observed in acute or chronic neurodegenerative diseases, microglia gets released from the inhibitory effect of neurons and astrocytes, showing activated phenotype either of its dual function. Microglia shows neuroprotective effect by secreting growths factors to heal neurons and clears cell debris through phagocytosis in case of a moderate stimulus. But the same microglia starts releasing pro-inflammatory cytokines like TNF-α, IFN-γ, reactive oxygen species (ROS), and nitric oxide (NO), increasing neuroinflammation and redox imbalance in the brain under chronic signals. Therefore, pharmacological targeting of microglia would be a promising strategy in the regulation of neuroinflammation, redox imbalance and oxidative stress in neurodegenerative diseases. Some studies present potentials of natural products like curcumin, resveratrol, cannabidiol, ginsenosides, flavonoids and sulforaphane to suppress activation of microglia. These natural products have also been proposed as effective therapeutics to regulate the progression of neurodegenerative diseases. The present review article intends to explain the molecular mechanisms and functions of microglia and molecular dynamics of microglia specific genes and proteins like Iba1 and Tmem119 in neurodegeneration. The possible interventions by curcumin, resveratrol, cannabidiol, ginsenosides, flavonoids and sulforaphane on microglia specific protein Iba1 suggest possibility of natural products mediated regulation of microglia phenotypes and its functions to control redox imbalance and neuroinflammation in management of Alzheimer's, Parkinson's and Multiple Sclerosis for microglia-mediated therapeutics.

Neuroinflammation in Parkinson's Disease: Triggers, Mechanisms, and Immunotherapies

Parkinson's disease (PD) is a heterogeneous neurodegenerative disease involving multiple etiologies and pathogenesis, in which neuroinflammation is a common factor. Both preclinical experiments and clinical studies provide evidence for the involvement of neuroinflammation in the pathophysiology of PD, although there are a number of key issues related to neuroinflammatory processes in PD that remain to be addressed. In this review, we highlight the relationship between the common pathological mechanisms of PD and neuroinflammation, including aggregation of α-synuclein, genetic factors, mitochondrial dysfunction, and gut microbiome dysbiosis. We also describe the two positive feedback loops initiated in PD after the immune system is activated, and their role in the pathogenesis of PD. In addition, the interconnections and differences between the central and peripheral immune systems are discussed. Finally, we review the latest progress in immunotherapy research for PD patients, and propose future directions for clinical research.

Metabotropic glutamate receptor 5 inhibits α-synuclein-induced microglia inflammation to protect from neurotoxicity in Parkinson's disease

Background

Microglia activation induced by α-synuclein (α-syn) is one of the most important factors in Parkinson’s disease (PD) pathogenesis. However, the molecular mechanisms by which α-syn exerts neuroinflammation and neurotoxicity remain largely elusive. Targeting metabotropic glutamate receptor 5 (mGluR5) has been an attractive strategy to mediate microglia activation for neuroprotection, which might be an essential regulator to modulate α-syn-induced neuroinflammation for the treatment of PD. Here, we showed that mGluR5 inhibited α-syn-induced microglia inflammation to protect from neurotoxicity in vitro and in vivo.

Methods

Co-immunoprecipitation assays were utilized to detect the interaction between mGluR5 and α-syn in microglia. Griess, ELISA, real-time PCR, western blotting, and immunofluorescence assays were used to detect the regulation of α-syn-induced inflammatory signaling, cytokine secretion, and lysosome-dependent degradation.

Results

α-syn selectively interacted with mGluR5 but not mGluR3, and α-syn N terminal deletion region was essential for binding to mGluR5 in co-transfected HEK293T cells. The interaction between these two proteins was further detected in BV2 microglia, which was inhibited by the mGluR5 specific agonist CHPG without effect by its selective antagonist MTEP. Moreover, in both BV2 cells and primary microglia, activation of mGluR5 by CHPG partially inhibited α-syn-induced inflammatory signaling and cytokine secretion and also inhibited the microglia activation to protect from neurotoxicity. We further found that α-syn overexpression decreased mGluR5 expression via a lysosomal pathway, as evidenced by the lysosomal inhibitor, NH₄Cl, by blocking mGluR5 degradation, which was not evident with the proteasome inhibitor, MG132. Additionally, co-localization of mGluR5 with α-syn was detected in lysosomes as merging with its marker, LAMP-1. Consistently, in vivo experiments with LPS- or AAV-α-syn-induced rat PD model also confirmed that α-syn accelerated lysosome-dependent degradation of mGluR5 involving a complex, to regulate neuroinflammation. Importantly, the binding is strengthened with LPS or α-syn overexpression but alleviated by urate, a potential clinical biomarker for PD.

Conclusions

These findings provided evidence for a novel mechanism by which the association of α-syn with mGluR5 was attributed to α-syn-induced microglia activation via modulation of mGluR5 degradation and its intracellular signaling. This may be a new molecular target for an effective therapeutic strategy for PD pathology.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-021-02079-1.

Rutin pretreatment promotes microglial M1 to M2 phenotype polarization

Microglial cells are important resident innate immune components in the central nervous system that are often activated during neuroinflammation. Activated microglia can display one of two phenotypes, M1 or M2, which each play distinct roles in neuroinflammation. Rutin, a dietary flavonoid, exhibits protective effects against neuroinflammation. However, whether rutin is able to influence the M1/M2 polarization of microglia remains unclear. In this study, in vitro BV-2 cell models of neuroinflammation were established using 100 ng/mL lipopolysaccharide to investigate the effects of 1-hour rutin pretreatment on microglial polarization. The results revealed that rutin pretreatment reduced the expression of the proinflammatory cytokines tumor necrosis factor-α, interleukin-1β, and interleukin-6 and increased the secretion of interleukin-10. Rutin pretreatment also downregulated the expression of the M1 microglial markers CD86 and inducible nitric oxide synthase and upregulated the expression of the M2 microglial markers arginase 1 and CD206. Rutin pretreatment inhibited the expression of Toll-like receptor 4 and myeloid differentiation factor 88 and blocked the phosphorylation of I kappa B kinase and nuclear factor-kappa B. These results showed that rutin pretreatment may promote the phenotypic switch of microglia M1 to M2 by inhibiting the Toll-like receptor 4/nuclear factor-kappa B signaling pathway to alleviate lipopolysaccharide-induced neuroinflammation.

Parkinson's Disease With Depression: The Correlations Between Neuroinflammatory Factors and Neurotransmitters in Cerebrospinal Fluid

Background: To explore the changes of neuroinflammatory factors in cerebrospinal fluid (CSF) and their correlation with monoamine neurotransmitters in Parkinson’s disease (PD) with depression (PD-D) patients.

Methods: Neuroinflammatory factors and neurotransmitters in CSF were measured and compared between PD with no depression (PD-ND) and PD-D groups. The relationship between PD-D and neuroinflammatory factors was studied by binary logistic regression equation, and the related factors of PD-D were adjusted. The correlations of the levels of neuroinflammatory factors and neurotransmitters in PD-D group were analyzed.

Results: The levels of tumor necrosis factor (TNF)-α in CSF from PD-D group were significantly higher and there were no significant differences in the levels of interleukin-1β, prostaglandin (PG) E₂, hydrogen peroxide (H₂O₂), and nitric oxide (NO). The 24-item Hamilton Depression Scale (HAMD-24) score was positively correlated with the level of TNF-α in CSF. Binary logistic regression showed that the OR of CSF TNF-α level was 1.035 (95% CI 1.002–1.069). The level of dopamine (DA) in CSF of PD-D group was significantly lower than that in PD-ND group. TNF-α level was negatively correlated with DA level in CSF from PD patients (r = −0.320, P = 0.003).

Conclusions: Neuroinflammatory factors, especially TNF-α, may play an important role in PD-D. It may cause damage to DA neurons and lead to the depletion of DA, which is related to the occurrence and development of PD-D.

The Role of P2X7 Receptor in Alzheimer's Disease

Alzheimer's disease (AD) is the most prevalent neurodegenerative disease characterized by a progressive cognitive decline associated with global brain damage. Initially, intracellular paired helical filaments composed by hyperphosphorylated tau and extracellular deposits of amyloid-β (Aβ) were postulated as the causing factors of the synaptic dysfunction, neuroinflammation, oxidative stress, and neuronal death, detected in AD patients. Therefore, the vast majority of clinical trials were focused on targeting Aβ and tau directly, but no effective treatment has been reported so far. Consequently, only palliative treatments are currently available for AD patients. Over recent years, several studies have suggested the involvement of the purinergic receptor P2X7 (P2X7R), a plasma membrane ionotropic ATP-gated receptor, in the AD brain pathology. In this line, altered expression levels and function of P2X7R were found both in AD patients and AD mouse models. Consequently, genetic depletion or pharmacological inhibition of P2X7R ameliorated the hallmarks and symptoms of different AD mouse models. In this review, we provide an overview of the current knowledge about the role of the P2X7R in AD.

Double triggers, nasal induction of a Parkinson's disease mouse model

Animal models of Parkinson's disease (PD), a chronic and progressive neurodegenerative disease of the central nervous system (CNS), play a key role in investigating the pathogenesis and developing new therapeutic strategies of PD. However, this goal has been limited by certain weaknesses in the available animal models of PD, e.g., induction by either pro-inflammatory or neurotoxic reagents, or they are too time-/effort-consuming. Here, we report a double triggers, nasal induction of a PD mouse model that mimics the clinical, pathological features and pathogenesis of PD by intranasal (i.n.) administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) combined with lipopolysaccharide (LPS). After administration once every three days for 7 consecutive weeks, these mice displayed enhanced motor dysfunction, loss of dopaminergic neurons, α-synuclein accumulation, as well as activation of microglia and astrocytes in the substantia nigra pars compacta compared with mice that were administered MPTP or LPS alone. This study provides a novel and basic research tool for investigating the pathogenesis and therapeutic intervention of PD.

Heterogeneity of Microglia Phenotypes: Developmental, Functional and Some Therapeutic Considerations

BACKGROUND

Microglia play a pivotal role in maintaining homeostasis in complex brain environment. They first exist as amoeboid microglial cells (AMCs) in the developing brain, but with brain maturation, they transform into ramified microglial cells (RMCs). In pathological conditions, microglia are activated and have been classified into M1 and M2 phenotypes. The roles of AMCs, RMCs and M1/M2 microglia phenotypes especially in pathological conditions have been the focus of many recent studies.

METHODS

Here, we review the early development of the AMCs and RMCs and discuss their specific functions with reference to their anatomic locations, immunochemical coding etc. M1 and M2 microglia phenotypes in different neuropathological conditions are also reviewed.

RESULTS

Activated microglia are engaged in phagocytosis, production of proinflammatory mediators, trophic factors and synaptogenesis etc. Prolonged microglia activation, however, can cause damage to neurons and oligodendrocytes. The M1 and M2 phenotypes featured prominently in pathological conditions are discussed in depth. Experimental evidence suggests that microglia phenotype is being modulated by multiple factors including external and internal stimuli, local demands, epigenetic regulation, and herbal compounds.

CONCLUSION

Prevailing views converge that M2 polarization is neuroprotective. Thus, proper therapeutic designs including the use of anti-inflammatory drugs, herbal agents may be beneficial in suppression of microglial activation, especially M1 phenotype, for amelioration of neuroinflammation in different neuropathological conditions. Finally, recent development of radioligands targeting 18 kDa translocator protein (TSPO) in activated microglia may hold great promises clinically for early detection of brain lesion with the positron emission tomography.

Neuroprotective effects of Danshensu on rotenone-induced Parkinson's disease models in vitro and in vivo

Background

Danshensu is an active constituent in the extracts of Danshen which is a traditional Chinese medical herb. Rotenone inhibits complex I of the mitochondrial electron transport chain in dopaminergic neurons leading to glutathione (GSH) level reduction and oxidative stress. The aim of this study is to investigate neuroprotective effects of Danshensu on rotenone-induced Parkinson’s disease (PD) in vitro and in vivo.

Methods

In vitro, SH-SY5Y human neuroblastoma cell line was pretreated with Danshensu and challenged with rotenone. Then the reactive oxygen species (ROS) production was assayed. In vivo, male C57BL/6 mice were intragastrically administered with Danshensu (15, 30, or 60 mg/kg), followed by oral administration with rotenone at a dose of 30 mg/kg. Pole and rotarod tests were carried out at 28 d to observe the effects of Danshensu on PD.

Results

Danshensu repressed ROS generation and therefore attenuated the rotenone-induced injury in SH-SY5Y cells. Danshensu improved motor dysfunction induced by rotenone, accompanied with reducing MDA content and increasing GSH level in striatum. Danshensu increased the number of TH positive neurons, the expression of TH and the dopamine contents. The expressions of p-PI3K, p-AKT, Nrf2, hemeoxygenase (HO-1), glutathione cysteine ligase regulatory subunit (GCLC), glutathione cysteine ligase modulatory subunit (GCLM) were significantly increased and the expression of Keap1 was decreased in Danshensu groups.

Conclusions

The neuroprotective effects of Danshensu on rotenone-induced PD are attributed to the anti-oxidative properties by activating PI3K/AKT/Nrf2 pathway and increasing Nrf2-induced expression of HO-1, GCLC, and GCLM, at least in part.

Pathophysiology and Therapeutic Perspectives of Oxidative Stress and Neurodegenerative Diseases: A Narrative Review

Introduction

Neurodegeneration is the term describing the death of neurons both in the central nervous system and periphery. When affecting the central nervous system, it is responsible for diseases like Alzheimer’s disease, Parkinson’s disease, Huntington’s disorders, amyotrophic lateral sclerosis, and other less frequent pathologies. There are several common pathophysiological elements that are shared in the neurodegenerative diseases. The common denominators are oxidative stress (OS) and inflammatory responses. Unluckily, these conditions are difficult to treat. Because of the burden caused by the progression of these diseases and the simultaneous lack of efficacious treatment, therapeutic approaches that could target the interception of development of the neurodegeneration are being widely investigated. This review aims to highlight the most recent proposed novelties, as most of the previous approaches have failed. Therefore, older approaches may currently be used by healthcare professionals and are not being presented.

Methods

This review was based on an electronic search of existing literature, using PubMed as primary source for important review articles, and important randomized clinical trials, published in the last 5 years. Reference lists from the most recent reviews, as well as additional sources of primary literature and references cited by relevant articles, were used.

Results

Eighteen natural pharmaceutical substances and 24 extracted or recombinant products, and artificial agents that can be used against OS, inflammation, and neurodegeneration were identified. After presenting the most common neurodegenerative diseases and mentioning some of the basic mechanisms that lead to neuronal loss, this paper presents up to date information that could encourage the development of better therapeutic strategies.

Conclusions

This review shares the new potential pharmaceutical and not pharmaceutical options that have been recently introduced regarding OS and inflammatory responses in neurodegenerative diseases.

A network pharmacology approach to investigate the anti-inflammatory mechanism of effective ingredients from Salvia miltiorrhiza

Salvia miltiorrhiza, known as Danshen in Chinese, has been widely used to treat cardiovascular diseases in China. Tanshinone I (Tan I) and cryptotanshinone (CST) are the lipid-soluble and effective components from Salvia miltiorrhiza. However, the molecular mechanism of Tan I and CST for treating inflammation is still not known. Therefore, this study was designed to use network pharmacology-based strategy to predict therapeutic targets of Tan I and CST against inflammation, and further to investigate the pharmacological molecular mechanism in vitro. Inflammation targets were identified and followed by acquisition of verified targets of Tan I and CST. After constructing target-functional protein interaction network of Tan I and CST against inflammation, the core therapeutic targets of Tan I and CST against inflammation were obtained. Further, pathway enrichment analyses were performed on core therapeutic targets to evaluate key signaling pathways of Tan I and CST against inflammation. As revealed in network pharmacology analysis, 8 key hub targets for Tan I and CST against inflammation were identified, respectively: JUN, VEGFA, IL-6, TNF, MAPK8, CXCL8, and PTGS2 for Tan I, while STAT3, AKT1, CCND1, MAPK14, VEGFA, ESR1, MAPK8 and AR for CST. Pathway enrichment analysis by DAVID database indicated that Tan I and CST principally regulated the inflammation-associated pathway, such as TLR, JAK-STAT signaling pathway, focal adhesion, apoptosis, mTOR signaling pathway. In vitro, we found that both Tan I and CST exerts significantly effect on LPS stimulated NO secretion and iNOS expression in macrophages. Taken together, our data elucidate that anti-inflammatory pharmacological activities of Tan I and CST may be predominantly related to inhibition of TLR signaling pathway and regulating iNOS synthesis. These findings highlight the predicted therapeutic targets may be potential targets of Tan I and CST for anti-inflammation treatment.

Pharmacological Targeting of Microglial Activation: New Therapeutic Approach

Mounting evidence suggests that neuroinflammation is not just a consequence but a vital contributor to the development and progression of Parkinson’s disease (PD). Microglia in particular, may contribute to the induction and modulation of inflammation in PD. Upon stimulation, microglia convert into activated phenotypes, which exist along a dynamic continuum and bear different immune properties depending on the disease stage and severity. Activated microglia release various factors involved in neuroinflammation, such as cytokines, chemokines, growth factors, reactive oxygen species (ROS), reactive nitrogen species (RNS), and prostaglandins (PGs). Further, activated microglia interact with other cell types (e.g., neurons, astrocytes and mast cells) and are closely associated with α-synuclein (α-syn) pathophysiology and iron homeostasis disturbance. Taken together, microglial activation and microglia-mediated inflammatory responses play essential roles in the pathogenesis of PD and elucidation of the complexity and imbalance of microglial activation may shed light on novel therapeutic approaches for PD.

Tanshinone I Inhibits IL-1β-Induced Apoptosis, Inflammation And Extracellular Matrix Degradation In Chondrocytes CHON-001 Cells And Attenuates Murine Osteoarthritis

Background

Osteoarthritis (OA) is a prevalent degenerative joint disease, which was characterized by inflammation and cartilage degradation. Accumulating evidence has demonstrated that Tanshinone I has an anti-inflammatory effect in various diseases. However, the efficacy of Tanshinone I as an anti-inflammatory agent in OA remains unclear. This study aimed to explore the role of Tanshinone I on OA both in vitro and in vivo.

Methods

CHON-001 cells were treated with IL-1β (10 ng/mL) for 72 hrs to induce OA model in vitro. Meanwhile, CHON-001 cells were pre-treated with 20 μM Tanshinone I for 24 hrs and then stimulated with IL-1β (10 ng/mL) for 72 hrs. CCK-8, immunofluorescence and flow cytometry assays were used to detect the viability, proliferation and apoptosis in CHON-001 cells, respectively. Western blotting assay was used to detect the levels of collagen II, aggrecan, MMP-13, cleaved caspase 1, Gasdermin D, SOX11 and p-NF-κB in CHON-001 cells. In addition, the mouse model of OA was built by anterior cruciate ligament transection (ACLT) in the right knee. Meanwhile, the mice were administrated with 10 or 30 mg/kg Tanshinone I for 8 weeks. Safranin-O/Fast Green staining was used to assess cartilage destruction in a mouse model of OA.

Results

In this study, IL-1β significantly induced apoptosis, extracellular matrix degradation and inflammatory response in CHON-001 cells. Tanshinone I significantly inhibited IL-1β-induced apoptosis in CHON-001 cells. In addition, the IL-1β-induced collagen II, aggrecan degradation, SOX11 downregulation, and MMP-13 and p-NF-κB upregulation in CHON-001 cells were notably reversed by Tanshinone I treatment. Moreover, Tanshinone I alleviated cartilage destruction and synovitis and reduced OARSI scores and subchondral bone thickness in a mouse model of OA.

Conclusion

Our findings showed that Tanshinone I could alleviate the progression of OA in vitro and in vivo. These results demonstrated that Tanshinone I might be regarded as a promising therapeutic agent for the treatment of OA.

Danshen extract (Salvia miltiorrhiza Bunge) attenuate spinal cord injury in a rat model: A metabolomic approach for the mechanism study

BACKGROUD

Spinal cord injury (SCI) is a devastating neurological disorder caused by trauma. To date, SCI treatment is still a significant challenge in clinic and research around the world. Danshen (dried roots and rhizomes of Salvia miltiorrhiza), a commonly used Chinese medicinal herb, has been attracting attention in SCI treatment.

PURPOSE

Aim of this study was to evaluate the potential beneficial effects of danshen extract in a SCI rat model, as well as investigate possible mechanism of action and potential biomarkers.

METHODS

Here, a rat SCI model was established with weight-drop method, and danshen extract was administered by oral gavage (12.5 g/kg). Recovery of motor function and histomorphological changes were evaluated by Basso, Beattie and Bresnahan score and hematoxylin-eosin staining, respectively. In addition, neurofilament 200 (NF-H), brain-derived neurotrophic factor (BDNF), glial fibrillary acidic protein (GFAP) and CD11b expressions were assayed by immunofluorescence and western blot analysis. Furthermore, a metabolomics analysis based on ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) approach was conducted.

RESULTS

The results demonstrated that danshen extract could significantly ameliorated histopathology changes and improved recovery of motor function after SCI. Moreover, NF-H, BDNF and CD11b expression were progressively increased until 4 weeks post-injury after administrated danshen extract. Furthermore, a good separation was observed among different groups using OPLS-DA. Trajectory analysis showed the gradual shift from position of model group toward normal group with increasing time after administration of danshen extract. Meanwhile, 51 significantly altered metabolites were identified, while metabolic pathway analysis suggested that 6 metabolic pathways were disturbed by the altered metabolites.

CONCLUSION

In summary, this study provides an overview of neuroprotective effects and investigates possible mechanism of danshen extract in SCI treatment. However, further research is needed to uncover its regulatory mechanisms more clearly.

Sodium tanshinone IIA sulfonate: A review of pharmacological activity and pharmacokinetics

Sodium tanshinone IIA sulfonate (STS) is a water-soluble derivate of tanshinone IIA (Tan IIA) which is an active lipophilic constitute of Chinese Materia Medica Salvia miltiorrhiza Bge. (Danshen). STS presents multiple pharmacological activities, including anti-oxidant, anti-inflammation and anti-apoptosis, and has been approved for treatment of cardiovascular diseases by China State Food and Drug Administration (CFDA). In this review, we comprehensively summarized the pharmacological activities and pharmacokinetics of STS, which could support the further application and development of STS. In the recent decades, numerous experimental and clinical studies have been conducted to investigate the potential treatment effects of STS in various diseases, such as heart diseases, brain diseases, pulmonary diseases, cancers, sepsis and so on. The underlying mechanisms were most related to anti-oxidative and anti-inflammatory effects of STS via regulating various transcription factors, such as NF-κB, Nrf2, Stat1/3, Smad2/3, Hif-1α and β-catenin. Iron channels, including Ca²⁺, K⁺ and Cl^- channels, were also the important targets of STS. Additionally, we emphasized the differences between STS and Tan IIA despite the interchangeable use of Tan IIA and STS in many previous studies. It is promising to improve the efficacy and reduce side effects of chemotherapeutic drug by the combination use of STS in canner treatment. The application of STS in pregnancy needs to be seriously considered. Moreover, the drug-drug interactions between STS and other drugs needs to be further studied as well as the complications of STS.

Danshen: a phytochemical and pharmacological overview

Danshen, the dried root or rhizome of Salvia miltiorrhiza Bge., is a traditional and folk medicine in Asian countries, especially in China and Japan. In this review, we summarized the recent researches of Danshen in traditional uses and preparations, chemical constituents, pharmacological activities and side effects. A total of 201 compounds from Danshen have been reported, including lipophilic diterpenoids, water-soluble phenolic acids, and other constituents, which have showed various pharmacological activities, such as anti-inflammation, anti-oxidation, anti-tumor, anti-atherogenesis, and anti-diabetes. This article intends to provide novel insight information for further development of Danshen, which could be of great value to its improvement of utilization.

Multiple pathways for natural product treatment of Parkinson's disease: A mini review

BACKGROUND

It is established that natural medicines for Parkinson's disease (PD) provide an antioxidant activity in preventing dopaminergic neurons from degeneration. However, the underlying and related molecular details remain poorly understood.

METHODS AND AIM

We review published in vitro and rodent studies of natural products in PD models with the aim to identify common molecular pathways contributing to the treatment efficacy. Commonly regulated genes were identified through the systemic literature search and further analyzed from a network perspective.

FINDINGS

Approximately thirty different types of natural products have been investigated for their ability to regulate protein density and gene activity in various experimental systems. Most were found to attenuate neurotoxin-induced regulations. Three common PD pathways are involved. The most studied pathway was neuronal development/anti-apoptosis consisting of Bax/Bcl-2, caspases 3/9, and MAPK signaling. Another well studied was anti-inflammation comprising iNOS, nNOS, Nrf2/ARE, cytokines, TNFα, COX2 and MAPK signaling. The third pathway referred to dopamine transmission modulation with upregulated VMAT2, DAT, NURR1 and GDNF levels. To date, HIPK2, a conserved serine/threonine kinase and transcriptional target of Nrf2 in an anti-apoptosis signaling pathway, is the first protein identified as the direct binding target of a natural product (ZMHC).

IMPLICATIONS

Natural products may utilize multiple and intercellular pathways at various steps to prevent DA neurons from degeneration. Molecular delineation of the mechanisms of actions is revealing new, perhaps combinational therapeutic approaches to stop the progression of DA degeneration.